National Institute of Standards and Technology

Computational Chemistry Comparison and Benchmark DataBase
Release 22	May 2022
NIST Standard Reference Database 101

I	Introduction
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XX	H-bond dimers
XXI	Oddities

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III.G.7. (XIII.B.3.) (XIII.D.5.)

Compare vibrational frequencies for two calculations for HOClO (Chlorous acid)

A = HF/6-31G*

B = MP2/6-31G*

scale factors=0.8985, 0.943

	symmetry			frequency (cm-1)					reduced mass (amu)					IR Intensity (km mol-1)
mode number	A	B		A	B	diff.	ratio		A	B	diff.	ratio		A	B	diff.	ratio
1	A	A		3614	3444	169.8	1.049		1.068	1.068	0.000	1.000		133.50	57.51	75.99	2.321
2	A	A		1264	1135	128.3	1.113		1.097	1.132	-0.035	0.969		63.09	86.75	-23.66	0.727
3	A	A		778	1102	-323.7	0.706		17.881	10.844	7.037	1.649		92.19	85.83	6.36	1.074
4	A	A		747	545	202.3	1.371		15.800	16.933	-1.133	0.933		35.61	148.61	-113.01	0.240
5	A	A		384	397	-13.6	0.966		2.753	1.270	1.483	2.168		132.14	153.01	-20.87	0.864
6	A	A		267	285	-17.8	0.937		1.668	5.970	-4.302	0.279		62.56	2.12	60.45	29.571
scaled by				0.8985	0.943

See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.